Seasonal Movements, Migratory Behavior, and Site Fidelity
of West Indian Manatees along the Atlantic Coast of the
United States as Determined by Radio-telemetry

Deutsch, Charles J. and Reid, James P. and Bonde, Robert K. and Easton, Dean E. and Kochman, Howard I.
(2000)
Seasonal Movements, Migratory Behavior, and Site Fidelity
of West Indian Manatees along the Atlantic Coast of the
United States as Determined by Radio-telemetry.
Gainesvilles, FL,
Florida Cooperative Fish and Wildlife Research Unit , University of Florida,

Abstract

The study area encompassed the eastern coasts of Florida, Georgia, and South Carolina,
including inland waterways such as the St. Johns River (Fig. 1). Manatees inhabited the
relatively narrow band of water that lies between the barrier beaches and the mainland,
occasionally venturing into the ocean close to shore. Between Miami and Fernandina Beach,
Florida, 19 inlets provided manatees with corridors between the intracoastal waters and the
Atlantic Ocean; the distance between adjacent inlets averaged 32 km(SD = 24 km) and varied
from 3 to 88 km. Habitats used by manatees along this 900-km stretch ofcoastline varied
widely and included estuaries, lagoons, rivers and creeks, shallow bays and sounds, and ocean
inlets. Salinities in most areas were brackish, but ranged from completely fresh to completely
marine. The predominant communities of aquatic vegetation also varied geographically and
with salinity: seagrass meadows and mangrove swamps in brackish and marine waters along the
southern half of peninsular Florida; salt marshes in northeastern Florida and Georgia; benthic
macroalgae in estuarine and marine habitats; and a variety of submerged, floating, and emergent
vegetation in freshwater rivers, canals, and streams throughout the region.
Radio-telemetry has been used successfully to track manatees in other regions ofFlorida
(Bengtson 1981, Powell and Rathbun 1984, Lefebvre and Frohlich 1986, Rathbun et al. 1990)
and Georgia (Zoodsma 1991), but these early studies relied primarily on conventional VHF (very
high frequency) transmitters and were limited in their spatial and temporal scope (see O'Shea
and Kochman 1990 for overview). Typically, manatees were tagged at a thermal refuge in the
winter and then tracked until the tag detached, usually sometime between the spring and fall of
the same year. Our study differs from previous research on manatee movements in several
important respects. First, we relied heavily on data from satellite-monitored transmitters using
the Argos system, which yielded a substantially greater number of locations and more systematic
collection of data compared to previous VHF tracking studies (Deutsch et al. 1998). Second, our
tagging and tracking efforts encompassed the entire range of manatees along the Atlantic coast,
from the Florida Keys to South Carolina, so inferences were not limited to a small geographic
area. Third, we often used freshwater to lure manatees to capture sites, which allowed tagging
in all months of the year; this provided more information about summer movement patterns than
had previous studies which emphasized capture and tracking at winter aggregations. Finally, the
study spanned a decade, and success in retagging animals and in replacing transmitters allowed
long-term tracking ofmany individuals. This provided the opportunity to investigate variation in
seasonal movements, migratory behavior, and site fidelity across years for individual manatees.
(254 page document.)

Item Type:

Monograph or Serial Issue

Title:

Seasonal Movements, Migratory Behavior, and Site Fidelity
of West Indian Manatees along the Atlantic Coast of the
United States as Determined by Radio-telemetry

Personal Creator/Author:

Creators

Email

Deutsch, Charles J.

Reid, James P.

Bonde, Robert K.

Easton, Dean E.

Kochman, Howard I.

Date:

2000

Publisher:

Florida Cooperative Fish and Wildlife Research Unit , University of Florida

Place of Publication:

Gainesvilles, FL

Projects:

Research Work Order no. 163, Sirenia Project, Florida Caribbean Science Center, National Biological Service